1. Field of the Invention
The present invention relates to a method of controlling a drying apparatus for a printing press, in which a matter to be dried (hereinafter referred to a drying matter) of a print is dried by irradiating light from a light source to the print, a drying apparatus and a printing press.
2. Related Art
A conventional drying apparatus hitherto known such as in Japanese Patent No. 2958955 (JP-A-1990-39940) is equipped with a light source (e.g., a UV (ultraviolet ray) lamp), from which light is irradiated on a print so as to dry a drying matter (e.g., printing ink and vanish) on the print. The drying apparatus of this type is disposed on a print conveying passage so as to subsequently dry drying matters of oncoming prints.
In the drying apparatus equipped with a light source that irradiates light on a print, the amount of light is generally easy to be decreased as the time for which the drying apparatus is used or the time for which light is irradiated elapses. This poses a problem that drying capability for drying matters of prints is deteriorated in response to the decrease of the amount of light.
In order to address the problem that the amount of light is decreased as the time for which the light source is lit is elapsed, a well-experienced operator manually adjusts the light-source control voltage that controls the light source based on his experience so as to allow the light source to irradiate a proper amount of light, thereby maintaining the drying capability of the drying apparatus for better result in drying operation.
However, an operator with less experience is hard to properly maintain the drying capability of the drying apparatus even by the manual adjustment to the amount of light of the light source, causing insufficient drying of prints. An insufficiently dried matter of each print might be smeared to the next print stacked thereon (set-off), or cause a print to be adhered to the next print, so that it is likely to cause a print to be discarded or broke unfit for use (hereinafter simply referred to-broke).
In consideration of the above problems, it is an object of the present invention to provide a method of controlling a drying apparatus that dries drying matters of prints by irradiating light of a light source on prints, which allows the drying apparatus to have a constant capability to dry the drying matters even in a case where the amount of light of the light source is decreased due to the elapse of the lighting time of the light source, thereby maintaining a good drying quality of prints, preventing set-off of drying matters and adhesion of a print to the next print and hence limiting production of broke. It is another object of the present invention to provide a drying apparatus and a printing press that can carry out this method.